Search results for "Background"
showing 10 items of 556 documents
Impact of general reionization scenarios on extraction of inflationary parameters
2010
Determination of whether the Harrison-Zel'dovich spectrum for primordial scalar perturbations is consistent with observations is sensitive to assumptions about the reionization scenario. In light of this result, we revisit constraints on inflationary models using more general reionization scenarios. While the bounds on the tensor-to-scalar ratio are largely unmodified, when different reionization schemes are addressed, hybrid models are back into the inflationary game. In the general reionization picture, we reconstruct both the shape and amplitude of the inflaton potential. We discuss how relaxing the simple reionization restriction affects the reconstruction of the potential through the c…
Primordial power spectrum features in phenomenological descriptions of inflation
2016
We extend an alternative, phenomenological approach to inflation by means of an equation of state and a sound speed, both of them functions of the number of $e$-folds and four phenomenological parameters. This approach captures a number of possible inflationary models, including those with non-canonical kinetic terms or scale-dependent non-gaussianities. We perform Markov Chain Monte Carlo analyses using the latest cosmological publicly available measurements, which include Cosmic Microwave Background (CMB) data from the Planck satellite. Within this parametrization, we discard scale invariance with a significance of about $10\sigma$, and the running of the spectral index is constrained as …
Institutions and Deontic Powers: Some Comments on the Tuomela-Searle Debate
In this talk I will analyze Tuomela’s theory of institutions and the most recent debate with Searle over the issue of whether institutions conceptually involve the creation and distribution of deontic powers. By way of analyzing Tuomela and Searle’s reciprocal criticisms, I conclude that Tuomela does not give us sufficient reasons to give up Searle’s thesis that institutions always involve deontic powers, but I also argue that it is necessary to go beyond Searle’s recent speech act-centered explanation of human sociality. More specifically, moving along the lines of Di Lorenzo’s view of constitutive rules as built into the logical and pragmatic structure of human activities, and making use …
Search for the Lepton Flavor Violation Process J/ψ→eμ at BESIII
2013
We search for the lepton-flavor-violating decay of the $J/\psi$ into an electron and a muon using $(225.3\pm2.8)\times 10^{6}$ $J/\psi$ events collected with the BESIII detector at the BEPCII collider. Four candidate events are found in the signal region, consistent with background expectations. An upper limit on the branching fraction of $\mathcal{B}(J/\psi \to e\mu)< 1.5 \times 10^{-7}$ (90% C.L.) is obtained.
Prospects for detecting the diffuse supernova neutrino background with JUNO
2022
We present the detection potential for the diffuse supernova neutrino background (DSNB) at the Jiangmen Underground Neutrino Observatory (JUNO), using the inverse-beta-decay (IBD) detection channel on free protons. We employ the latest information on the DSNB flux predictions, and investigate in detail the background and its reduction for the DSNB search at JUNO. The atmospheric neutrino induced neutral current (NC) background turns out to be the most critical background, whose uncertainty is carefully evaluated from both the spread of model predictions and an envisaged in situ measurement. We also make a careful study on the background suppression with the pulse shape discrimination (PSD) …
Experimental investigations of the hypernucleus $_Λ^4$H
2015
International audience; Negatively charged pions from two-body decays of stopped _Lambda^4H hypernuclei were studied in 2012 at the Mainz Microtron MAMI, Germany. The momenta of the decay-pions were measured with unprecedented precision by using high-resolution magnetic spectrometers. A challenge of the experiment was the tagging of kaons from associated K^+∧ production off a Be target at very forward angles. In the year 2014, this experiment was continued with a better control of the systematic uncertainties, with better suppression of coincident and random background, improved particle identification, and with higher luminosities. Another key point of the progress was the improvemen…
Management of Bleeding Complications in Virtual Reality Laparoscopy
2019
The aim of this study was to compare the impact of induced bleeding complication training with regular training on a virtual reality laparoscopic (VRL) simulator. Although bleeding complications occur rarely during laparoscopic surgery, they usually arise without warning and may have severe consequences for the patient because complication management training is not currently widespread. Third-year medical students (n = 41) were randomly selected for 2 curricular courses on how to perform a bimanual task on a VRL simulator. Both the regular training group (RTG) and the induced bleeding complication training (ICT) group performed 2 regular training sessions and 9 training sessions. For the I…
Distillation and stripping pilot plants for the JUNO neutrino detector: Design, operations and reliability
2019
Abstract This paper describes the design, construction principles and operations of the distillation and stripping pilot plants tested at the Daya Bay Neutrino Laboratory, with the perspective to adapt these processes, system cleanliness and leak-tightness standards to the final full scale plants to be used for the purification of the liquid scintillator of the JUNO neutrino detector. The main goal of these plants is to remove radio impurities from the liquid scintillator while increasing its optical attenuation length. Purification of liquid scintillator will be performed with a system combining alumina oxide, distillation, water extraction and steam (or N 2 gas) stripping. Such a combined…
Light Dark Matter Search with Ionization Signals in XENON1T
2019
We report constraints on light dark matter (DM) models using ionization signals in the XENON1T experiment. We mitigate backgrounds with strong event selections, rather than requiring a scintillation signal, leaving an effective exposure of (22±3) tonne day. Above ∼0.4 keVee, we observe <1 event/(tonne day keVee), which is more than 1000 times lower than in similar searches with other detectors. Despite observing a higher rate at lower energies, no DM or CEvNS detection may be claimed because we cannot model all of our backgrounds. We thus exclude new regions in the parameter spaces for DM-nucleus scattering for DM masses mχ within 3–6 GeV/c2, DM-electron scattering for mχ>30 MeV/c2, a…
Australian TESOL Teachers’ Cultural Perceptions of Students
2017
ABSTRACTOver the last decade, research in the field of Teaching English to Speakers of Other Languages (TESOL) has increasingly focused on the relationship between culture and learning. Researchers such as Kumaravadivelu (2003) have been vocal in their opposition to the practice of cultural stereotyping. In the current study, Holliday’s (2005) model of Culturism was used as a theoretical basis. Six Australian TESOL teachers were interviewed to determine the nature and extent of the cultural stereotypes that they held, particularly as they pertained to specific learning-related behaviours. A qualitative analysis of the data revealed that teachers most often grouped students in terms of natio…